Although the Cessna 172 etc. are not approved for flight in icing conditions, the cabin air / windshield demister or whatever does prevent ice built-up on the windshield in real life, don’t ask how I know 
. But even without and in severe icing conditions, icing will NEVER look like it does in MSFS. It will never impair vision that much. The type and extend in MSFS is completely wrong, it looks like very extensive frost which you would expect on ground after parking in freezing fog overnight, not inflight icing.
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